Sources of destructive high-speed transient events may range from a lightning stroke during a thunderstorm to an electrostatic discharge (ESD) from a human finger. High-speed electrical transient events may originate inside a facility or on the electrical grid, and may propagate through various levels of electrical and data systems. High-speed transient voltages that exceed insulation ratings may stress electrical insulation, leading to abrupt failure or gradual breakdown of the dielectric material. Industrial facilities may experience many transient events every hour, with voltage impulses exceeding 5 to 10 times the nominal system voltage. Reducing the magnitude, duration, and quantity of transient events may extend the life of equipment insulation.
Transient events typically last from less than a microsecond to several milliseconds. Transient voltages are generally classified into normal mode or common mode, depending on where they occur on a power system. Normal-mode transient voltages appear between any two power or signal conductors. Common-mode transient voltages generally appear equally and in-phase from each power or signal conductor to ground. Because the damage due to transient voltages at times is subtle, identifying transients as the cause of damage to a component is difficult, and is often diagnosed as “unknown.”
The effect of a transient event on a specific load will depend on the load's level of susceptibility to transients. The influence of a transient event on electronic equipment generally falls into one of four categories: 1) intermittent interruption; 2) chronic degradation; 3) latent failure; and 4) catastrophic failure.
Intermittent interruptions may occur when a transient event is injected into a data or control network resulting in lost or corrupted data. This may result in the load or device locking up, tripping off, or operating improperly. Factors that can affect a transient's ability to disturb a load include design and operating speed of semiconductors, system filters, grounding configuration, susceptibility to electromagnetic interference (EMI) and radio frequency interference (RFI), and the configuration of the data or control cable.
Chronic degradation may occur when repetitive transient events diminish the integrity of an exposed component (or components). Over time (generally days, weeks, or even months), the cumulative effect of transient voltages results in the eventual failure of the vulnerable component.
Latent failures are similar to chronic degradation, except that they are precipitated by a significant transient event that damages components, but not to the point that the component cannot perform its intended function. Over some period of time (again, days, weeks, or even months), the ordinary stresses due to normal operation will ultimately result in the component's inoperability. Latent failures are more difficult to troubleshoot because the root cause may have occurred at any time in the past.
Catastrophic failures due to transient events cause the affected component to immediately cease to operate and damage may be visible. Catastrophic failures result from the magnitude, duration, or rate of rise of the transient exceeding the rated threshold of the component to create a permanent open circuit or short circuit within the component. Solid-state products, microprocessor-based devices, and programmable logic controllers (PLCs) are especially susceptible to damage from voltage transients. Accordingly, exposure to transient events can reduce the reliability and shorten the life of such devices. As technology evolves and the scale of these devices shrinks, their susceptibility to damage from the harmful characteristics associated with high-speed transient events increases.
High-speed transient events can interfere with the normal operation of equipment resulting in erratic behavior and the diminished quality of the equipment's end product. Furthermore, interruptions in continuous manufacturing processes can result in revenue losses due to production downtime.
Failure to take remedial action to eliminate transient events can lead to equipment failure or other anomalies such as a hard drive crash, parity errors, power supply failure, component failure, lock up, memory scramble, SCR failure, or speed or setting drift.
What is needed, therefore, is a system to allow users to determine the location of transient events in an electrical system. There is also a need for a system to determine transient characteristics data to effectively troubleshoot and remedy high-speed transient events in an electrical power system. There is a further need for a system and method to assist in determining the most effective technique to mitigate the effects of a given transient source type. There is also a need for a system to determine the effectiveness of an applied solution to detection of a transient source type. There is also a need for a system of transient detection devices installed on an electrical power system for reliable transient information. Aspects of the present invention described herein fulfills these and other needs.